Non-gelling heavy duty liquid laundry detergent

ABSTRACT

A CLEAR NON-GELLING LIQUID SYNTHETIC ORGANIC HEAVY DUTY LAUNDRY DETERGENT COMPOSITION COMPRISING A NONIONIC DETERGENT HAVING THE MOLECULAR CONFIGURATION OF THE CONDENSATION PRODUCT OF A HIGHER FATTY ALCOHOL AND ETHYLENE OXIDE, AN ANIONIC DETERGENT HIGHER FATTY ALKYL POLYETHENOXY SULFATE, A BRIGHTENING AGENT, WATER AND A LOWER MONOHYDRIC ALCOHOL. SMALL PROPORTIONS OF SEQUESTERING AGENTS AND SALT-FORMING BASES MAY ALSO OPTIONALLY BE PRESENT IN THE COMPOSITION. THE DETERGENT COMPOSITION IS A SINGLE PHASE CLEAR STABLE LIQUID BUT MAY BE MADE OPAQUE, CREAMY OR OPALESCENT IF DESIRED. FURTHERMORE, THE COMPOSITION IS SUBSTANTIALLY NEUTRAL OR ONLY SLIGHTLY ALKALINE WHEN MEASURED AT A 1% CONCENTRATION IN WATER AND CLEANS SOILED LAUNDRY TO A DEGREE COMPARABLE WITH THAT OBTAINED UTIHLOZING PHOSPHATE BUILT ALKALINE DETERGENTS. IN ADDITION, THE LIQUID DETERGENT COMPOSITION IS BIODEGRADABLE.

3,812,041 NON-GELLING HEAVY DUTY LIQUID LAUNDRY DETERGENT Jack ThomasInamorato, Westfield, N.J., assignor to Colgate-Palmolive Company, NewYork, N.Y. No Drawing. Filed June 23, 1972, Ser. No. 265,721 Int. Cl.Clld 1/83 US. Cl. 25289 17 Claims ABSTRACT OF THE DISCLOSURE A clearnon-gelling liquid synthetic organic heavy duty laundry detergentcomposition comprising a nonionic detergent having the molecularconfiguration of the condensation product of a higher fatty alcohol andethylene oxide, an anionic detergent higher fatty alkyl polyethenoxysulfate, a brightening agent, water and a lower monohydric alcohol.Small proportions of sequestering agents and salt-forming bases may alsooptionally be present in the composition. The detergent composition is asingle phase clear stable liquid but may be made opaque, creamy oropalescent if desired. Furthermore, the composition is substantiallyneutral or only slightly alkaline when measured at a 1% concentration inwater and cleans soiled laundry to a degree comparable with thatobtained utilizing phosphate built alkaline detergents. In addition, theliquid detergent composition is biodegradable.

This invention relates to a substantially neutral liquid detergentuseful for heavy duty laundering of soiled clothing and other cloth orfabric articles. More particularly, this invention relates to asubstantially builder-free clear biodegradable liquid detergentcomposition which functions comparably to conventional phosphate builtor nitroliotriacetate built commercial heavy duty laundry detergents.

In recent years there has been a sharply increasing awareness ofpossible disruptive effects on the ecology attending discharge ofvarious pollutants into ground waters, streams, rivers and lakes.Particularly undesirable is the large ,scale discharge of compoundswhich persist in the environment and adversely affect the quality of ourwaters. As a resultof governmental and individual concern, manufacturesof detergent compositions are attempting to eliminate non-biodegradablesynthetic organic detergent materials, i.e. branchedchain alkyl benzenes'ulfonates, as the organic surface active agents in commerciallyavailable'household laundry detergents. Along with such research, thereare extensive efforts to replace the'polyphosphate builder constituentsin such detergent compositions so that the wash water discharge fromhousehold and commercial laundries will not cause possible accumulationsof phosphates in rivers and lakes.

-The elimination of these polyphosphates from commercial and householddetergents has not been-without its attendant difliculties since thesematerials have very desirable building, sequestering and soil-suspendingactivities and the removal of these materials from the detergentcompositions results in significant losses in cleaning power. Adetergent composition comprising only active synthetic organicdetergents does not produce the same cleaning effect as a combination ofthese detergents and the polyphosphates. At the present time, the onlysubstitute for the polyphosphates which appears to be approximatelyequal with regard to building and soil-suspending eflects are thenitrilotriacetic acids and acetates often referred to as NTA.

The present liquid'detergents are based on a combination of an ethoxamersulfate and a nonionic detergent both of which are readilybiodegradable. Utilization, however, of non-ionic detergents, althoughbiodegradable, is

United States Patent 3,812,041 Patented May 21, 1974 not without itsattendant drawbacks. The use of non-ionic detergents in liquid detergentcomposition must be balanced against the tendency of these materials togel upon standing in open contact with the atmosphere. Furthermore, someof these non-ionic detergents subsequent to prolonged contact with theatmosphere are not readily dispersible in water and gel upon contactwith the same. In accordance with the composition of the presentinvention, however, it has been found that by utilizing certain specificnon-ionic detergents this gelling phenomenon is reduced or eliminatedaltogether, thereby permitting nonionic biodegradable detergents havingdetersive properties similar to prior art alkaline built detergentcompositions to be prepared in the-absence of polyphosphates and otherinorganic builder salts or alkaline materials. Although the compositionof the present invention may include a small amount of NTA, or the like,acting as a metal sequestrant, to prevent discoloration of the productsand laundry washed, these small amounts of NTA and the like do not haveany building effect on the overall composition.

In the clear liquid products, various constituents aid in solubilizingother components so that the product is clear and concentrated yetreadily pourable. Furthermore, repeated test washings indicate that thecleaning power of the biodegradable detergents is approximatelyequivalent to other commercial built detergent compositions in cleaningaction against realistic body soil and actual laundering tests in homelaundry washing machines and against mixed loads under variousconditions.

It is within the above environment and background that the novelcomposition of the present invention was developed. Briefly, suchcomposition comprises a non-ionic detergent, at least 50% of thenon-ionic detergent comprising a lower molecular weight non-ionic havingthe formula RO(C H O),,H, wherein R is an alkyl group, preferably astraight chain alkyl group having from 10 to 15 carbon atoms, Rgenerally is in the form of a mixed alkyl and may comprise either onespecific chain length or a mixture of up to all six, n is selected from6 to 11' with the proviso that n' is from about /5 to about 3 of theaverage number of carbon atoms in R; the remainder vention to provide anon-gelling heavy of the non-ionic detergent comprises a highermolecular weight non-ionic having the formula RO (C H O),,H,' wherein Ris an alkyl group preferably a straight chain alkyl group averaging from14 to 20 carbon atoms and n is a number of from 10 to 14, n beingfrom'about -to 1 times the number of :carbon atoms in R; an anionicethoxamer sulfate, i.e. polyethenoxy sulfate of the formula RO(C HO),,SO M wherein R is a fatty alkyl of from 10 to 20 carbon atoms, n isfrom 2 to 6 and preferably from /5 to /3. of the number of carbon atomsin R and M is a salt-forming ion usually selected from alkali metals,ammonium, lower alkylamino or lower alkanolamino; a minor proportion ofa fluorescent brightener system that is normally at least partiallywater-soluble; water; and an alcohol with the proportion of thenon-ionic and anionic detergents, fluorescent brightener system, waterand alcohol bring such that the insoluble fluorescent brightener issubstantially in solubilized form.

It is therefore the primary object of the present induty liquid laundrydetergent.

It is a further object of the present invention to provide abiodegradable liquid detergent which is stable on st'and ing when it isexposed to the atmosphere.

It is a still further object of the present invention'to provide a heavyduty liquid detergent containing substantially no builders with acleaning proformance substantially equal to alkaline phosphate builtdetergents.

Still further objects and advantages of the composition of the presentinvention will become more apparent from the following more detaileddescription thereof.

The novel liquid non-gelling detergent which is devoid of phosphate andnitrogenous builders of the present invention comprises from 25% to 75%weight percent of a non-ionic detergent, this non-ionic detergentcomprising from 100% to 50% by weight of the non-ionic of a lowmolecular weight non-ionic of the formula RO(C H O),,H wherein R is analkyl group preferably having a straight chain from 10 to 15 carbonatoms and n is a number from 6 to 11 with the proviso that n is from /5to of the average number of carbon atoms in R, and from to 50% by weightof the non-ionic of a high molecular weight non-ionic of the formulaRO(C H O),,H wherein R is an alkyl group preferably having a straightchain of from 14 to 20 carbon atoms and n is a number of from 10 to 14,n generally comprising 4 to 1 times the number of carbon atoms in R;from to 25 by weight of an ethoxamer sulfate of the formula wherein R isa fatty alkyl of from to 20 carbon atoms, n is from 2 to 6 andpreferably from /s to /3 of the number of carbon atoms in R and M is asalt-forming ion generally selected from alkali metals, ammonium, loweralkylamino or lower alkanolamino, the total non-ionic and anionic inweight ratio of from :1 to 1:1 0.5 to 5% by weight of a fluorescentbrightener system which is generally at least partially water-soluble, 5to 35% by weight of water and 5 to 35% by weight of a lower alkanol.

The synthetic organic detergents utilized in the present invention whichprovide the concentrated clear liquid detergent composition with itsnon-gelling characteristics comprise the lower molecular weightnon-ionic condensation products of a fatty alcohol with ethylene oxideor ethylene glycol optionally containing a small proportion of propyleneglycol. Normally, this condensation will be with ethylene oxide which ischeaper and does not require the removal of by-product water. Methodsfor the manufacture of such compounds are well known and these materialshave been previously employed in detergent compositions, althoughgenerally their use has been limited to being part of the entire activeorganic detergent portion of light duty liquid detergents. The lowmolecular weight non-ionics which provide the composition of the presentinvention with the non-gelling characteristics are of the formula RO(C HO),,H wherein R is an alkyl group preferably having a straight chain offrom 10 to 15 carbon atoms and n is from 6 to 11 with the proviso that nis from Vs to V of the average number of carbon atoms in R. Generally,due to the methods of manufacture, mixed alkyls are employed and for thecomposition of the present invention to have the desired non-gellingcharacteristics it is preferred to utilize mixed alkyl chains whereinthe chain length averages approximately 12. Furthermore, the ethyleneoxide which reacts with these mixed alkyls 'will also vary somewhatWithin the abovenoted range of from 6 to 11. The ethylene oxide contentcan vary within this range as long as the amount of ethylene oxide inthe final product is within the parameter of from /s to of the averagenumber of carbon atoms in the alkyl group. Since it is critical tomaintain the proper balance of fatty alkyl chain length and ethyleneoxide chain length within the above-noted ranges in order to obtain gooddetersive properties together with the nongelling property andcompatibility with other materials, it has been found and is a preferredembodiment of the present invention to utilize a non-ionic detergent ofthe above formula wherein R is a mixed straight chain alkyl having from10 to 15 carbon atoms, the average number of carbon atoms averagingapproximately 12, and n is from 6 to 9 with the proviso that n is fromV5 to V5 of the average number of carbon atoms in R. Preferred nonionicswhich have a minimum of gel characteristics include Neodol 25-7 (Requals mixed 12-15 carbon atom alkyl, n equals 11 average value) made byShell Chemical Company and Pluorofac B-26, the reaction product of alinear alcohol with a mixture of ethylene and propylene oxides, made byWyandotte Chemical Company.

The non-ionic detergent portion of the heavy duty liquid detergent ofthe present invention may also contain up to 50% of a high molecularweight non-ionic detergent of the formula RO(C H O) H wherein R is astraight chain alkyl of from 14 to 20 carbon atoms and n is from 10 to14 with the proviso that n is from tol times the average number ofcarbon atoms in R. As with the lower molecular weight non-ionics whichimpart the non-gelling characteristics to the composition of the presentinvention, these higher molecular weight non-ionics are also produced byreacting mixed alkyls with ethylene oxide chains which include differentchain lengths within the 10 to 14 ethylene oxide radical range. Withinthis range, as noted above, there is a desirable hydrophilic-lipophilicbalance which is necessary in order to obtain good detersive propertiestogether with other desirable properties and compatibility with otherdetergent composition ingredients. Generally, the alkyl group will befrom 14 to 16 carbon atoms and usually the average carbon content ofpreferred compounds are from 14 to 15 and in the most preferred highermolecular weight non-ionic detergent compositions for use with the lowermolecular weight nonionies, the alkyl groups will be over 14 to 15carbon atom chain lengths. Similarly, it is preferable to have from 10to 12 ethylene oxide radicals per chain and in a most preferredembodiment these will average about, and very preferably be equal toabout 11 ethylene oxide units-per chain. A preferred higher molecularweight non-ionic to be utilized in the composition of the presentinvention is Neodol 45-11 (R equals mixed 14 to 15 carbon atom alkyls, nequals 11 average value) made by Shell Chemical Company. The desiredhydrophilic-lipophilic balance is maintained by keeping n equal to aboutto 1 times R.

In addition to the chain lengths of the hydrophilic-lipophilic portionsof the high molecular weight and low molecular non-ionic detergentsdescribed above for best detergency and biodegradability it is importantthat such portions be of certain configurations. Of necessity, theethylene oxide chain will be linear and terminated by a free hydroxyl.Also, as in the case of Pluorofac B-26, some mixed chains of ethyleneoxide and propylene oxide may be utilized although pure ethylene oxidechains are generally preferred. The alkyl groups also most preferablywill be linear although a minor degree of slight branching such as at acarbon next to or two carbons removed from the terminal carbon of astraight chain and away from the ethoxy chain, may be tolerated providedthat such branched alkyl portion is of no more than 3 carbon atoms inlength. Usually, the portion of carbon atoms in such branchedconfiguration will be quite minor, rarely being more than 20 or 10% ofthe entire alkyl content of carbon atoms. Also, although linear alkylswhich are terminally joined to the ethylene oxide chains are highlypreferred and result in best detergency, biodegradability and otherimportant properties including non-gelling characteristics, medial orsecondary joinder to the ethylene oxide in the chain may occur in aminor proportion of such alkyls and generally such proportion will beless than 20% and preferably less than 10% thereof. With regard to theinclusion ofminor quantities of propylene oxide in the ethylene oxidechain, it is preferred that the ethylene oxide chain consistsessentially of ethylene oxide, generally over 80% and preferably overthereof.

The composition of the present invention also includes an anionicdetergent. Such anionic detergent is a sulfated ethoxylated higher fattyalcohol of the formula RO(C H O),,SO M

wherein R is at fatty alkyl of from to 20 carbon atoms, n is from 2 to6, being from A to /3 of the number of carbon atoms in R and M is asolubilizing salt-forming cation such as an alkali metal, ammonium,lower alkylamino or lower alkanolamino. As with the non-ionicdetergents, this anionic detergent is most readily biodegradable and ofbetter detergency when the fatty alkyl is terminally joined to thepolyoxyethylene chain, which, of course, is terminally joined to thesulfur-forming sulfate group. Again, although slight branching of thealkyl chain may be tolerated to the extent of not more than 10% of thecarbon atom content as noted above with regard to the non-ionicdetergents, this minor deviation from the linear structure is to beespecially avoided in the anionic detergents. Furthermore, medialjoinder of the alkyl group to the polyoxyethylene chain should beminimal, less than 10%, and even such joinder then should be preferablyconcentrated near the end of the alkyl chain. Within the 10 to 20 carbonatom alkyl groups, the preferred alkyls are of 12 to carbon atoms andthose which are most preferred are mixed alkyls containing 12, 13, 14and 15 carbon atom chains. The mixture is preferably one containing atleast 10% of each chain length and no more than 50% of any one chainlength.

The ethylene oxide content of the anionic detergent is such that n isfrom 2 to 6 and is preferably from 2 to 4, generally averaging about 3,especially when R is a mixed 12 to 15 carbon atom alkyl. To maintain adesired hydrophilic-lipophilic balance, when the carbon content of thealkyl chain is in the lower portion of the 10 to range, the ethyleneoxide content might be reduced so that n is about 2, whereas when R isof 16 to 18 carbon atoms, n may be from 4 to 6. The salt-forming cationmay be any suitable solubilizing metal or radical but will mostfrequently be alkali metal or ammonium. If alkyl-amine or loweralkanolamine groups are present, alkyls and alkanols thereof willusually contain one to four carbon atoms and the amines andalkanolamines may be mono-, dior tri-substituted, e.g. monoethanolamine,diisopropanolamine, trimethylamine.

The importance of using the correct anionic detergent in the presentcompositions is shown by the failure of corresponding alcohol sulfatesin similar liquid detergent compositions to wash as well as the presentcompositions containing the described higher alcohol-ethylene oxidesulfates. For example, a higher alcohol sulfate in which the alcohol ismixed 12 to 15 carbon atom alcohol, exhibits a significantly poorerdetergency in liquid compositions like those of the present invention,compared to the corresponding ethoxylated sulfate in the samecomposition. Even within the preferred range of alcoholethylene oxidesulfates, an improvement in detergency is noted for the compositionswhich include a mixed 12 to 15 carbon atom alcohol-ethylene oxidesulfate, when compared to other higher alcohol-ethylene oxide sulfates,such as a mixed 14 to 15 carbon atom alcohol-ethylene oxide sulfate ofthe same ethylene chain length. The preferred detergent is availablefrom Shell Chemical Company and is'identified by them as Neodol 3S, thesodium salt, normally sold as a 60% active material, including about 40%of aqueous solvent medium, of which a minor proportion is ethanol.Although Neodol 25-38 is the sodium salt, the potassium salt and othersuitable soluble salts may also be used either in partial or completesubstitution for that of sodium.

Examples of the higher alcohol polyethenoxy sulfates which may be usedas the anionic detergent constituent of the present liquid compositionor as partial substitutes for this include: mixed C normal primary alkyltriethenoxy sulfate, sodium salt; myristyl triethenoxy sulfate,potassium salt; n-decyl diethenoxy sulfate, diethanolamine salt; lauryldiethenoxy sulfate, ammonium salt; palmityl tetraethenoxy sulfate,sodium salt; mixed C1445 normal primary alkyl mixed triand tetraethenoxysulfate, sodium salt; stearyl pentaethenoxy sulfate, trimethylamine saltand mixed C1048 normal primary alkyl triethenoxy sulfate, potassiumsalt. Minor proportions of the corresponding branched chain and mediallyalkoxylated detergents, such as those described above but modified tohave ethoxylation at a medial carbon atom, e.g. one located four carbonsfrom the end of the chain, may be employed but the carbon atom contentof the higher alkyl will be the same. Similarly, the joinder of a normalalkyl may be at a secondary carbon one or two carbon atoms removed fromthe end of the chain. In either case, only the minor proportionspreviously mentioned will be present.

For most of the heavy duty liquid detergents it will be unnecessary andundesirable to utilize active detergent ingredients other than the highand low molecular weight non-ionics and anionic combination describedabove. Yet, for some applications minor proportions of supplementarydetergents may be used. These will generally be of the nonionic typealthough in some formulations other anionic, cationic, amphoteric orampholytic detergents or surface active agents of known types may beemployed. For example, there may be used higher fatty acid esters ofpolyethylene glycols, block copolymers of ethylene oxide and propyleneoxide, higher alkyl-di-lower alkyl amine oxides, the sodium salts of thesulfuric acid derivatives of higher fatty alcohol condensation productswith ethylene oxide, triethanolamine lauryl sulfate, straight chainalkyl sulfonates, sodium lauroyl sarcoside, cetyl trimethylammoniumbromide, benzethonium chloride, dimethyl dibenzyl ammonium chloride,N-higher alkyl N,N- di-lower alkyl aminopropane sulfonates,amidosulfobetaines, betaines and amidobetaines. Descriptions of suchadditional detergents may be found in the text, Synthetic Detergents, bySchwartz, Perry and Berch, published in 1958 by Interscience Publishers,New York, see pp. 25- 143. It will be kept in mind that such materialswill be employed only for specific purposes and in small proportions,compared to the detergent combination of the low and high molecularweight higher fatty alcohol-ethylene oxide non-ionics and thealkyl-ethylene oxide sulfate anionic and will usually be used when aspecific cleaning property thereof is desirable for a particularapplication.

The fluorescent or optical brighteners or whiteners employed areimportant constituents of modern detergents which give washed laundryand materials a bright appearance so that the laundry is not only cleanbut also looks clean. Due to the variety of synthetic fibersincorporated in the textiles which are made into clothing and otheritems of laundry and the importance of substantivity of the brightenercompound to the fibers, many different fluorescent brightening compoundshave been made, which may be incorporated in the present detergentcompositions, often in mixtures. Of course, brighteners, suitable foruse on cotton, and brighteners which are stable in the presence ofoxidizing bleaches are also of importance. Therefore, although it ispossible to utilize only a single brightener for a specific intendedpurpose, in the compositions of the present invention it is generallyimportant to utilize a mixture of brighteners which will have goodbrightening effects on cotton, nylons, polyesters, and blends of suchmaterials and which, additionally, are bleach stable. A good descriptionof such types of optical brighteners is given in the articles, OpticalBrighteners and Their Evaluation, by Per S. Stensby, a reprint ofarticles published in Soap and Chemical Specialties in April, May, July,August and September 1967, especially at pp. 3-5 thereof.

The cotton brighteners, frequently referred to as CC/ DAS brightenersbecause of their derivation from the reaction product of cyanuricchloride and the disodium salt of diamino-stilbene disulfonic acid inmolar proportion of 1:2 are bistriazinyl derivatives of4,4'-diaminostilbene-2,2'-disulfonic acid. In most cases, the CC/DAS 7is reacted with two moles of aniline or sulfanilic or metanilic acid andthe product is additionally substituted on the 'triazine rings. Suchcompounds are of the general formula: I

wherein X may be either hydrogen or SO Na and the Rs may be thosederived from aniline, morpholine, N-methylethanol amine ordiethanolamine. Because some heavy duty laundry detergents will beemployed in conjunction with bleach, a bleach stable brightener, usuallya benzidine sulfone disulfonic acid, a naphthatriazolylstilbene sulfonicacid or a benzimidazolyl derivative will be used. These compounds are ofthe formulas:

SIO Na SOaNa wherein R may be hydrogen, lower alkyl, lower alkanol,lower aminoalkanol, anilino, morpholino, etc. The polyamide brighteners,especially good for nylons, are usually either aminocoumarin or diphenylpyrazoline derivatives. Unfortunately, neither of these is especiallystable in the presence of chlorine bleaches. The compounds are of theformulas given below and the R and the R groups thereof may bepreviously listed as substituents on the optical brighteners discussedearlier, while X and Y may include such substituents as halogens andlower alkyls.

The polyester brighteners, which are becoming of more importance aspolyesters are being used to a greater extent in an increasingproportion of textiles are usually of one of the following formulas,wherein R, X andY have the meaning previously given and Z may beselected from the group of X and Y substituents. These brighteners alsousually serve to 'whiten polyamides.

The brighteners are used in their acid forms or as salts. They may beemployed as solids or in solutions and may be cut with a carrier powder.Although the chemical and physical forms can affect brightening actions,if the compounds are used in soluble forms brightening activities forthe same compounds on an active ingredient basis will be equivalent. Inthe present compositions and in the wash waters resulting, thebrighteners are maintained sufiiciently soluble so as to be effectiveand uniformly substantive to the materials of hte laundry being washed.

Among the brighteners that are used in the present systems are:Calcofiuor White ALF (American Cyanamid); ALF-N (American Cyanamid); SOFA-200l (CIBA); CDW (Hilton-Davis); Phorwite RKH (Verona); CSL, powder,acid (American Cyanamid); PE 766 (Verona); Blancophor PD (GAF) UNPA(Geigy) Tinopal RBS (Geigy); and RES 200 (Geigy). The acid or nonionicforms of the brighteners tend to be solubilized by alcohols of thepresent formulas, while the salts tend to be water soluble. *lhus, acombination of such solvents and the detergent combination serve to keepthe fluorescent brighteners dissolved.

The lower alkanol employed is preferably either ethanol of isopropanolbut can be any lower monohydric alcohol. Of the two preferred alcoholsethanol is most preferred because of a slightly greater solubilizingpower and more pleasant odor. If ethanol is used, it will normally bedenatured and of the denatured alcohols those identified as SD40 or 3Aare preferred. However, other denatured alcohols may also be used. Thealcohols need not be anhydrous and the small proportions of waternormally present with them are considered to be part of the watercomponents of the liquid detergents. Some or all of the alcohol may bereplaced with dihydric or trihydric lower alcohols which, in addition tohaving solubilizing powers and reducing the flash point of the product,also can act as anti-freezing constituents and may improvecompatibilities of the solvent system with particular productcomponents. Among these compounds, the most preferred group includes thelower polyols of 2 to 3 carbon atoms, e.g. ethylene glycol, propyleneglycol and glycerol, but the lower alkyl (C -C etheric derivatives ofsuch compounds known as Cellosolves, may also be employed, generally toonly a minor extent.

The water used is preferably deionized so that it will be low in contentof ions which can form insoluble compounds. However, ordinary tap watercan be used providing that the hardness thereof is sufiiciently low sothat in the formula employed there is no detrimental precipitation outof salts on standing. When sequestrants are present, hardness will beless important and in such cases even waters with hardnesses over 300parts per million equivalent calcium carbonate can be acceptable.Generally, however, the water hardness should be less than p.p.m. andmost preferably, less than 50 p.p.m.

The sequestering agent, when used, may be any suitable compound,including the aminopolycarboxylic acids and hydroxycarboxylic acids.Thus, ethylene diamine tetraacetic acid, nitrilotriacetic acid,hydroxyalkyl derivatives thereof in which the hydroxyalkyl groupreplaces one or more acetic acid groups, gluconic acid, ascorbic acid,glucono-delta-lactone (which is converted to gluconic acid), citricacid, lactic acid and salts thereof, especially those of the watersoluble alkali metals, e.g. sodium, potassium, etc, ammonium,alkanolamines and amines, may be used. Other sequestering orwater-softening agents of the inorganic type such as certain phosphatesmay be used in very small amounts if desired but are not present inamounts suflicient to have a builder function.

Adjuvants may be present in the liquid detergent to give it additionalproperties, either functional or aesthetic. Thus soil suspending oranti-redeposition agents, may be used such as, polyvinyl alcohol, sodiumcarboxymethyl cellulose, hydroxypropylmethyl cellulose; enzymes, e.g.protease amylases; thickeners, e.g., gums, alginates, agar agar;hydrotropes, e.g. sodium xylene snlfonate, ammonium benzene sulfonate;foam improvers, lauric myristic diethanolamide; foam destroyers, e.g.silicones, bactericides, e.g. tribromosalicylanilide, hexachlorophene;fungicides; dyes; pigments (water dispersible); preservatives;ultraviolet absorbers; fabric softeners; pearlescing agents; opacifyingagent, e.g. behenic acid; polystyrene suspensions, and perfumes. Ofcourse, such materials will be selected for the properties desired inthe finished product and to be compatible with the other constituentsthereof.

The pH of the heavy duty liquid detergent composition will normally besubstantially neutral or only slightly alkaine. The composition of thepresent invention contains a minimum of akaline material per se, sincethe particulate soil removal of the particular non-ionic and anionicdetergents utilized is enhanced in approximately neutral solutions.However for various reasons, such as solubilizing and neutralizingvarious brighteners used, a small amount of an alkaline material may beincluded. Suitable alkaline materials include mono-, diandtrialkanolamines, alkylamines, ammonium and alkali hydroxides. Thepreferred alkali materials are the alkanolamines, especially thetrialkanolamines and most especially triethanolamine. A pH reading ofthe liquid detergent using a glass electrode and a reference calomelelectrode, indicates a maximum pH of about 8. However, because thedetergent system is essentially non-aqueous despite the presence of aminor proportion of water, the pH reading obtained may be false. Abetter indication is obtained by measuring the pH of a 25 solution inwater. This should usually be in the range of about 6.8 to 8.8. In watercontaining items to be laundered the pH will normally be within the samerange.

The proportion of the various components of the present heavy dutyliquid detergents are important to the obtainment of a uniform productand acceptable heavy duty laundering action. In the absence of asignificant builder content, it is very important that the productcontain a significant proportion of detergents. So as to promotesolubility of the fluorescent brighteners and other constituents andmake a clear, homogeneous and readily pourable liquid product, from 25to 75% of the total liquid detergent concentrate should be non-ionicfatty alcohol-ethylene oxide condensation products in a mixture of from100% to 50% by weight of non-ionic of low molecular weight non-ionic andfrom to 50% by weight of high molecular weight non-ionic as describedabove. The preferred range is from 30 to 60% of total nonionics and inthe most preferred embodiment of the invention about 40% is employed. Itis preferred that the non-ionic mixture comprise a significant portionof low molecular weight non-ionic since the non-gelling properties ofthis material are more effective at higher concentrations. According, itis preferred to utilize a non-ionic mixture of from 100% to 75% byweight of the non-ionic of low molecular weight non-ionic and from 0 to25% by weight of the non-ionic of high molecular weight nonionic, and itis most preferred to use all low molecular weight non-ionic. For thegreatest effectiveness, the quantity of the anionic ethoxamer sulfatedetergent should be within the range of about 5 to 20% and preferablyabout A of the total non-ionic content, i.e. preferably 10%. Suitableweight ratios of total non-ionic to anionic ranges from about 15:1 to1:1 with 8:1 to 2:1 preferred and 5 :1 to 3 :1 most preferred.

The concentration of fluorescent or optical brightener or whiteningagent in the product will be from about 0.5 to 5% on an activeingredient basis, preferably about 1 to 3% and most preferably about 2%.Such quantities are readily solubilized in the clear liquid product andcontribute substantially to brightening of fabrics in the laundry.Generally, 25% and preferably at least 50% of the optical brightenercontent will be a brightener for cotton. It is preferred to use about 51to 90% of a cotton brightener, with the balance being one or more ofpolyamide brighteners, polyester brighteners, and chlorinestablebrighteners.

The lower alcohol will generally be present in a sufficient proportionto aid in stabilizing or dissolving various constituents of the productsuch as the brighteners. The proportion employed will generally be from5 to 35%, preferably from 5 to 25 When used without supplementing diolor triol, the quantity of alcohol present normally is from 5 to 20% butwhen the supplementing polyol is used the content of alcohol may bereduced to from 5 to 15%, preferably about 5 to 10%. In suchcircumstances, the proportion of polyol will generally be from 5 to 15most preferably 10%. The percentage of water utilized will alsogenerally be from 5 to 35% and a preferred range is from 5 to 25 with amost preferred range being from 15 to 20%. Similar considerationsprevail in determining the proportion of water to be employed as do inthe case of the alcohols.

The non-building proportion of sequestrant, when used, may range from0.2 to 3,%, preferably from 0.5 to 1.5%, and most preferably 0.8%.

Considering the wide range of adjuvants which may be utilized, forwidely different purposes, the quantities or proportions thereofemployed will vary. Generally, however, it may be said that the totalthereof should not exceed 10% and will preferably be maintained lessthan 5% and more preferably less than about 3%. Individual componentsshould usually not exceed 5% preferably 3% and more preferably 1% of theproduct. The use of more of such compounds will often significantlychange the properties of the liquid detergent and, therefore, is to beavoided.

The heavy duty liquid detergents of the present invention can be made bysimple manufacturing techniques which do not require any complicatedequipment or expensive operations. In a typical manufacturing method,the optical brighteners may be slurried in the monohydric alcohol ormixture of monohydric and polyhydric alcohol. If initially slurried inthe monohydric alcohol, subsesequently the polyhydric alcohol, if used,may be added to this. Then water and, if necessary, a small amount ofbase such as triethanolamine is added, which helps to partially dissolvethe previously suspended material but not yield a clear solution.Addition of the detergent combination causes the remainder of thebrightener to dissolve to make a clear solution. Then the sequestrant,if used, may be added as the acid or salt (preferably the sodium,potassium or amine salt) and agitation is continued until the solutionbecomes clarified, which will normally take about 5 to 10 minutes. Atthis point perfume and dye may be added to give the product its finaldesired appearance and odor. All of the operations may 'be effected atroom temperature, although suitable temperatures within the range of 10to C. may be employed, as desired. Additions of adjuvants may beefiected at suitable points in the process but for the most part thesewill be added to the final product. The product obtained will usuallyhave a pH within the range of from 6.5 to 8, e.g. 7.0 and a densitywithin the range of from 0.9 to 1.1, preferably from 0.95 to 1.05 andmost preferably from 0.98 to 1.02. The viscosity of the product at 25C., will usually be from 20 to 200 centipoises, preferably from 50 to150 cps., and will be in the higher part of this range if a polyhydricalcohol is used in replacement of some lower monohydric alcohol.

Use of the present compositions is marvelously simple and eificient.Compared to present heavy duty laundry detergent powders, much smallervolumes of the present liquids may be employed to obtain cleaning ofsoiled laundry. For example, in a typical and preferred formulation ofthis invention, containing about 40% of the fatty alcohol-ethylene oxidecondensate and ethoxamer sulfate, only about 2 ounces or A cup of liquidneed to be used for a full top-loading automatic machine tube of d wash,in which the water volume might be from 15 to 18 gallons. Thus, theconcentration of liquid detergent in the wash water is on the order of0.1%, 1 gram per liter or 1,000 parts per million. Generally, theproportion employed will be from 0.7 to 1.5 grams per liter, which maycorrespond to 0.3 to 0.6 g./l. of the mixture of fatty alcohol-ethyleneoxide condensation products, from 0.075 to 0.15 g./l. of ethoxamersulfate, from 0.01 to 0.05 -g./l. of the fluorescent or opticalbrightener, from 0.05 to 0.4 g./l. of lower monohydric alcohol and from0.005 to 0.03 g./l. of organic sequestrant. The proportions of otherconstituents of the liquid compositions may vary accordingly. Of course,equivalent results can be obtained by using larger proportions of a moredilute liquid deter-gent but the greater quantity needed will requireadditional packaging and shipping space and will be less convenient forthe consumer to use. However, it is considered that the use of such moredilute products is within the present invention if the relativeproportions of components is maintained. In other words, the presentinvention is not avoided by merely preliminarily diluting the liquiddetergent with wash water also serves to dilute the detergent down to awater since the same end result is obtained because the useconcentration.

Although it is preferred to employ wash water of reasonable hardness andat an elevated temperature, the present invention is also useful inlaundering clothes and other items in hard waters and in extremely softwaters, as well as in waters at room temperature or below. Thus, waterhardnesses may range from 0 to over 300 parts per million as calciumcarbonate and washing temperatures may be from 10 C. to 80 C.Preferably, the temperatures will be from room temperature, 20 to C., to70 C. Also, although washing will ordinarily be effected in an automaticwashing machine, with the washing followed by rinse and spin or drainingor wringing operations, it is contemplated that the detergent may alsobe used for hand washing of laundry. In such cases, the concentration inwater of the liquid detergent will often be increased and sometimes itmay be full strength to assist in washing out otherwise difficult toremove soils or stains. After completion of the washing and spinningoperations, it will be general practice to dry the laundry in anautomatic dryer soon thereafter but such particular drying operation isnot necessary.

When the liquid detergent is added to water, whether that water is hotor cold, the detergent immediately dissolves uniformly throughout thewash water, even in the absence of significant agitation. Washing andbrightening agents are carried into contact with all the laundry andthere are no localized over-concentrations of either of these materials.The clothing washed, following normal methods, is exceptionally cleanand in compartive tests the product has been rated as good as some ofthe best commercial heavy duty detergents on the market. Al-

though it is a lowand non-foaming detergent composition and thus verysuitable for side-loading washing machines, excellent washing is alsoobtained in top-loading machines in which foaming detergents arenormally employed. Repeated testing of soiled and re-soiled laundryitems, using the present compositions and larger quantities ofcommercial heavy duty detergents built with phosphate or NTA, show thatthe soilings are repeatedly removed and no objectionable build-upthereof occurs. For the most part, users do not note any reallysignificant differences between the washing properties of the presentcomposition and commercial compositions tested. In fact, there has beena significant preference for the present product.

If the low molecular weight non-ionic detergents are omitted from thecomposition and replaced with higher molecular weight non-ionicdetergents having a similar hydrophilic-lipophilic balance, the liquidcomposition gels within a short period of time when exposed to theatmosphere. Furthermore, the liquid detergents without sufficient lowmolecular weight non-ionic, i.e. at least 50% of the non-ionicdetergents, to retard or eliminate this gelling do not disperse properlyin water after exposure to the atmosphere. If the liquid detergent gelsand does not disperse properly in water, this causes the brighteners tobe concentrated in small areas causing uneven and splotchy brightening.

The discovery of the present compositions and their exceptionally goodproperties was unexpected because those skilled in the art have notexpected to be able to make an unbuilt heavy duty laundry detergentcomposition without the use of inorganic builder salts or EDTA or NTAsubstitutes for such builders. This was especially surprising in view ofthe previous use of the present organic detergents only as light dutycleaning agents, since their ability to remove soil from laundry inheavy duty applications was unappreciated. Also, it was a conclusioncontrary to that formerly reached by many other research workers in thefield of detergency. The use of the compositions of the presentinvention without NTA has no adverse effect on the substantivity of theoptical brighteners whereas sequestrants of the NTA or polyphosphatetypes can interfere with the even deposition of brighteners on laundry.As a matter of fact, surprisingly, outstanding whiteness values areobtained by the unique combination of the instant non-ionics andanionics. The detergent does not react with hypochlorite bleacheswhereas NTA can undergo such reactions. Finally, the variousconstituents of the detergents, as was previously mentioned, help tomutually solubilize one another and form a flowable clear liquid, Thealcohols and water solubilize the brightener system and the detergentcondensate aids in producing best solubility and a clear product. Thelow molecular weight non-ionic prevents the liquid detergent fromgelling. Gel prevention means stain prevention, because otherwisestaining of the wash could occur due to deposits of gel holding thebrightcner to only some parts of the laundry. This detergent liquid iseasily biodegradable and does not add quantities of phosphate orsubstitute NTA builder to the wash water.

The composition of the present invention will now be more fullyillustrated by the following specific examples which are illustrativeand in no way limitative of the present composition wherein all partsand percentages are by weight and temperatures in degrees Fahrenheitunless otherwise noted.

EXAMPLE 1 A clear, liquid detergent having the following formula isprepared by slurrying the mixture of optical brighteners in SD-40alcohol followed by the addition of water and triet hanolamine withstirring. Subsequently, the Neodol 25-7 and the Neodol 25-3S is addedand after a few minutes of agitation at moderate speed the solutionbecomes clear.

13 RO(C H O)-;H (Neodol 25-7, R=mixed 12, 13, 14 and 15 carbon atomsprimary alkyl) RO(C I-I O) SO Na (Neodol 25-3S, R=mixed 12, 13, 14 and15 carbon atoms primary al- 1 A: 4,4 bis[(4-anilino 6methylamino-Striazine-2-yl) amino]2,2-stllbenedisulfonic acid; dlsodiumsalt.

3:4,4. bis[(4-anllino-6-[bis(2-hydroxy-ethyl)arnlnol-S-triazine-2-yl)amino]-2,2'-stilbenedisulfonic acid, disodium salt.C=4-naphthotrlazolyl-2-stilbenesulfonic acid, sodium salt.

4 D:2- (1,3dsoindazo1e) -2- (naphth [1,2d] oxazole) stilbene.

The pH of a 25% solution of the above formulation in water is about 7.0.This liquid detergent which is a sparkling, clear, free-flowing liquidis then packed in polyethylene plastic bottles of substantially cubicshape and of one quart capacity and is ready for use. Storage testsindicate that this product Will be stable for several years withoutprecipitation of insoluble salts, settling into a plurality of phases,clouding or other disadvantageous effects on appearance or function.

Furthermore, if the above formulation is allowed to sit in contact withthe atmosphere, the same will not gel even after 18 hours exposure tothe air and further after exposure to the air, when poured into hot orcold Water, is readily dispersed therein.

Detergency and brightening power of the liquid detergent composition isevaluated in control tests wherein the experimental formula is comparedwith various commercial heavy duty ecology type laundry detergents. Inthese tests, cloths are intentionally soiled with a mud soil and washedin identical washing machines (Terg-o-tometer)"using the same Water andrecommended amounts of the experimental and various controlleddetergents. The soiled cloths are collected and divided so that'theexperimental and controlled formulas are used to Wash similarly soiledloads of laundry. Such testing is repeated and the whiteness of thevarious washed cloths are compared each time by Reflectometer. Resultsof these tests in both hot and cold washing water conditions are listedin Table 1.

TABLE 1 120 F. conditions Rd. values Product Cone. 1st wash 2d washExample 1 0. 09 82.5 83. 7 0. 30 67.5 67.8 0.30 63.1 60. 5 0.175 70.0 V66. 5 0.26 52. 3 56. 7 0. 15 74. 9 78. 2

70 F. conditions Example 1 0. 09 80 4 78. 4

' Exam 1e: conlpanson p 0. 175 72. 2 70. 0 0.30 73. 7 74. 9 0. 26 59. 264. 1

In the above-noted table, the higher Rd. or Refiectometer valuesindicate a whiter wash. From the abovenoted table it is clear that theproduct of Example 1 cleans better at a lower concentration than othercommercially available ecology type, i.e. biodegradable andnon-phosphate containing, detergent compositions. Furthermore, theformulation of Example 1 cleans better at a lower wash waterconcentration as exhibited in Table 1 14 which shows that aconcentration of only 0.09 is necessary as opposed to up to 0.3 for someother ecology type detergents.

From the above it is apparent that the present formulation can beutilized in a concentration which corresponds to approximately cup per16-gallon automatic washing machine tube and that at such concentrationthe liquid detergent favorably compares with other washing productswherein concentrations corresponding to 1% cups of spray-dried heavyduty laundry detergents must be used. Furthermore, Reflectometerreadings of Whiteness when the formulation of Example 1 is comparedagainst various laundry detergents built with polyphosphates show nosignificant difference between the detergents. Furthermore, subjectiveevaluations of the product in consumer tests using a panel of housewivesresult in a significant preference for the liquid detergent.

Since no builder is utilized, it has been theorized that particulatesoil could accumulate on washed items, however, subsequent to repeatedwashings shows that the laundry detergent of Example 1 compares quitefavorably with the phosphate detergents with regard to particulate soilremoval.

EXAMPLE 2 A series of liquid detergent compositions are producedutilizing the basic formula of Example 1 where in the Neodol 25-7 isreplaced with the following non-ionic detergents:

(A) C1243 alcohol-+6.5 moles of ethylene oxide (B) C1245 alcohol-F9moles of ethylene oxide ((3) C alcoh0l+6 moles of ethylene oxide (D) Calcohol-l-S moles of ethylene oxide (E) Wyandotte Plurofac B-26 1 (F)Jefferson Chemical Co. Surfonic L4 1 (G) C1445 alcohol-H1 moles ofethylene oxide (H) C1448 alcohol+11 moles of ethylene oxide (I) C1645alcohol+ 11 moles of ethylene oxide (J) C alcohol-H2 moles of ethylene(K) 1:1 mixture of C +11 EO and Pluorofac B-26 mixture Of C16 18+11 andC12 13-6.5

1 Linear alcohol+a mixture of ethylene and propylene oxide.

. When each of the above-noted detergent formulations are tested inaccordance with the open-beaker gel test, i.e. the liquid detergentformulation is left in an uncovered beaker and is observed for gelformulation, detergents and do not gel after exposure to the atmospherefor 18 hours and are readily dispersible in water. However,-formulations (G), (H), (I) and (J) all containing higher molecularnon-ionic detergents gel within 5- minutes subsequent to exposure to theatmosphere and as gelled are not easily dispersed in water. As ungelleddetergents, however, all of the above formulations possess adequatecleaning and detersive characteristics when compared both to phosphatebuilt detergents and ecology type commercial detergents.

' EXAMPLE 3 (A) 0.1:1 (D 0.75:1 (B) 0.251 (E) 1.25:1 c 0.511 (F) 1.5;1

When each of the above-noted samples is subjected to the open-beaker geltest, Samples (A) through (D) do not gel within 18 hours and aredispersed readily upon pouring into both hot and'cold water. Samples3(E) and 15 (F), however, became gelled within minutes exposure to theatmosphere and are not readily dispersible in hot or cold water.

EXAMPLE 4 Examples 2(A) through (F) and (K) and (L) are repeated varyingthe total amount of non-ionic detergent from 40% to the following with aconcomitant increase or decrease in total amount of water and alcohol:

(A) 20% (D) 45% (B) 25% (E) 50% (C) 30% (F) 60% Each of the above-noteddetergent compositions cleaned quite well and possessed good detersiveproperties although those with a lower percentage of non-ionicdetergents and those with lower and upper percentages did not cleanquite as well as those wherein the amount of non-ionic materials wasapproximately 40%.

EXAMPLE 5 Examples 2(A) through (F), (K) and (L) are re peated exceptthat the following anionic detergent materials are substituted forNeodol 25-3S:

(A) C ether sulfate containing 2 moles of condensed ethylene oxide (B) Cether sulfate containing 2 moles of condensed ethylene oxide (C) C ethersulfate containing 5 moles of condensed ethylene oxide (D) C ethersulfate containing 3 moles of condensed ethylene oxide (E) C ethersulfate containing 6 moles of condensed ethylene oxide.

Each of the above-noted detergent concentrations also possessedexcellent detersive properties and was non-gelling upon standing whentested by the open-beaker gel test.

While the composition of the present invention has been illustrated byway of the foregoing specific examples, the composition of the presentinvention is to be in no way limited thereto but to be construed asbroadly as any and all equivalents and as properly defined in thefollowing appended claims.

What is claimed is:

1. A clear, non-gelling, heavy duty liquid detergent composition devoidof phosphate and nitrogenous builders and which consists essentially of:

(a) from 25 to 75% of a detergent mixture of at least one non-ionicdetergent and an anionic detergent in a weight ratio ranging from :1 to1:1, said nonionic detergent comprising from 100 to 50% by weight basedon the weight of the non-ionic detergent of a (3 43 fatty alcoholethoxylate containing from 6 to 11 moles of condensed ethylene oxide,with the proviso that the number of moles of condensed ethylene oxide isfrom to an of the average number of carbon atoms in the fatty alcoholand from 0 to 50% by weight of a C -C fatty alcohol ethoxylatecontaining from 10 to 14 moles of condensed ethylene oxide the number ofmoles of ethylene oxide being M to 1 times the number of carbon atoms inthe fatty alcohol, said anionic detergent comprising a sulfatedethoxylated C -C fatty alcohol containing about 2 to 6 moles ofcondensed ethylene oxide;

(b) sufficient lower alkanol to solubilize the detergent mixture; and

(c) from 5 to 35% of water, said liquid detergent being substantiallyneutral in water.

2. The detergent composition of claim 1 wherein the ratio of totalnon-ionic to anionic is from 8:1 to 2:1.

3. The detergent composition of claim 1 wherein the amount of anionic isabout A of the total amount of non-ionic.

4. The detergent composition of claim 1 wherein the fatty moiety of saidsulfated alcohol contains from 12 to 15 carbon atoms.

5. The detergent composition of claim 4 wherein said fatty moietycomprises mixed alkyl containing from 12 to 15 carbon atoms and whereinat least 10% and not more than 50% of each member of said mixed alkyl ispresent.

6. The composition of claim 1 wherein the total nonionic detergentcomprises 40% by weight of the composition and said anionic detergentcomprises 10% by weight of the composition.

7. The composition of claim 1 wherein the non-ionic detergent comprisesa mixed C1z-C15 fatty alcohol ethoxylate containing about 7 moles ofcondensed ethylene oxide.

8. The detergent composition of claim 1 wherein said lower alkanolcomprises a C -C monohydric or polyhydric alcohol or mixtures thereof.

9. The detergent composition of claim 8 wherein said alkanol is amixture based on total composition of 5 to 15 of polyhydric alcohol withthe remainder being monohydric alcohol.

10. The detergent composition of claim 1 which further includes fromabout 0.5 to 5% of a bleach stable, at least partially water solublefiourescent or optical brightener.

11. The detergent composition of claim 10 wherein said brightenercomprises cotton, polyamide and/or polyester brightener.

12. The detergent composition of claim 10 wherein said brightenercomprises a mixture of A=4,4-bis[(4-anilino 6 methylamino S triazine-2-yl)amino]-2,2'-stilbenedisulfonic acid, disodium salt,

B=4,4' bis[(4 anilino 6 [bis(2 hydroxy-ethyl) amino] S triazine 2yl)amino] 2,2 stilbenedisulfonic acid, disodium salt.

C=4-naphthotriazolyl-Z-stilbenesulfonic acid, sodium salt, and

D=2-(1,3-isoindazole) 2 (naphth[l,2-d]oxazole) stilbene.

13. The detergent composition of claim 11 wherein from 51 to 90% of saidbrightener is cotton brightener.

14. The detergent composition of claim 1 including from about 0.2 to 3%of aminopolycarboxylic acid or hydroxy carboxylic acid sequesteringagent.

15. The detergent composition of claim 1 containing an alkaline materialselected from the group consisting of mono-, diand trialkanolamines,alkylamines, ammonium and alkali hydroxides.

16. The detergent composition of claim 15 wherein said alkaline materialcomprises triethanolamine.

17. A process of laundering which comprises contacting cloth or fabricwith aqueous media containing from 0.7 to 1.5 g./l. of the compositionof claim 1, said containing being carried out at a temperature of fromabout 10 to C.

References Cited UNITED STATES PATENTS 2,920,045 1/ 1960 Hearn et al.252Dig. 14 2,943,058 6/ 1960 Cook 252Dig. 14 3,179,599 4/ 1965 Eaton etal 252Dig. 14- 3,231,504 1/ 1966 Marion et al 252551 3,562,170 2/1971Zorayan et a1 252551 FOREIGN PATENTS 836,774 6/ 1960 Great Britain252Dig. 14

WILLIAM E. SCHULZ, Primary Examiner US. Cl. X.R. 252551, Dig. 1

